Member Since: 14 Nov 2015
Location: bristol
Posts: 46
fresh idea for getting around trailer LED strobe problem?
I have a 2006 RRS and have the common trailer LED strobing problem. Ive been over and over this forum and looked all all the options, but i didnt seem to see what i plan todo.
My range rover didnt come with any towing electrics. So i decided to fit a 13pin socket with dedicated wiring. It was very cheap (£75) and was simple to fit.
I often need to run a 13pin to 7pin adaptor for boat trailers etc (this is where i use the LED trailer lights.)
The adaptor lead i run has both the 7N and 7S plugs/leads.
I never use the 12v power lead. So i plan to remove it, and use the 12v ingition power in the 13pin to power up the cheap bypass relays on ebay. And just run that for the green and yellow idicator wires. (As well as 2x 50W 6.8 ohm resistors so the car can see the trailer.) And have all this in the adaptor lead. So it keeps it remote and removable from the car. I think it will work. What do the experts think?
See attached pics. The red and black wire shown by my thumb are 12v and neutral ignition power that i can use to power the bypass relay box.
[/img]
1st Mar 2016 9:04 pm
EstorilM
Member Since: 15 Oct 2009
Location: Virginia
Posts: 28
Haha yikes, have you confirmed that this is indeed a "problem?"
I'm fairly certain at some point in the technical workshop manuals' description and operation (or maybe somewhere else) the body control computer is always sending out a "sensing pulse" onto the brake light circuits of the trailer electrics harness.
I've had a few hints that this is the case, including the fact that when the vehicle is "asleep" it will not do this - only when the modules/computers energize like when you re-open a door or unlock the vehicle.
Initially I thought it was a safety feature for visibility when I first got my RRS but I've read some other stuff since then.
Also, you know it's not a "problem" with LEDs specifically right? The vehicle is pulsing that circuit on ALL trailers with ALL lights.
I'm guessing the pulse checks resistance to ground on that circuit - and on most trailers back in 2004 or whatever when these things were being developed, the standard incandescent bulbs don't respond fast enough for you to even notice this. I realized this on my first boat trailer w/ the RRS because two of the lights still had standard non-LED bulbs and THOSE would not illuminate with the pulses (but the vehicle was still doing it and was visible on the LED housings).
So anyways, it is normal. Why are you trying to defeat something LR engineered the vehicle to do? AFAIK the pulsing stops after you wait long enough or lock the vehicle. It's a few millisecond pulse anyways that uses zero current so I doubt it could ever kill your battery - like ever ever.|'99 Discovery II | 177k mi. | Kinversand | 7 pas, SLS, HK|
|'06 LR3 HSE Luxury | Chawton White | Cold Weather/Adaptive HL/RSE/Running Boards | '14 "blackout" LR4 tail lights, 2.5" lift rods, 20" black/machined stormers, 275/55/20 Falken Wildpeaks
2nd Mar 2016 2:44 pm
lamb190
Member Since: 14 Nov 2015
Location: bristol
Posts: 46
All correct what you say,
However the canbus systems send pulses down the trailer electrics (as you said- when its awake) and this causes the lights to strobe.
This inline harness im making is plug play so will not effect the OEM tow electrics thats in my car.
I need to somthing for my boat trailers as i cant drive down the motorway with the LED trailer lights strobing or ill get pulled by the cops every 10 miles or so.
2nd Mar 2016 5:13 pm
romadog2004
Member Since: 07 Nov 2010
Location: Powys
Posts: 290
Cyclists seem allowed to do it !!!
Here we go.......
2nd Mar 2016 6:48 pm
Sly666
Member Since: 15 Dec 2014
Location: East Sussex
Posts: 459
My boat trailer trailer LED lights work perfectly.
I fitted the bypass relay box as show above. This will stop the strobing LEDS, however as the bypass relay adds no load to the the vehicles electrics the car does not know its towing.
The dashboard towing indicator does not flash when indicating (legal requirement for MOT test)
The car apparently runs a different suspension program on the rear suspension when towing which it wont do.
Also the car will disable the rear reversing sensors when it detects a trailer present.
To get around this you need to fit some power resistors to the left and right indicators on the trailer LED lights.
This is pretty straight forward on something like a caravan, but as my boat trailer lights are submersible they are sealed.
You could put the resistors in a waterproof box somewhere on the trailer chassis, but as salt water and trailer electrics dont mix, i opted to mount them in the Discovery boot panel, with a double pole switch to turn on when towing.
Works a treat, Let me know if you want the wiring diagram and parts list.
2nd Mar 2016 11:49 pm
lamb190
Member Since: 14 Nov 2015
Location: bristol
Posts: 46
Ive already saved a copy of your wiring diagram you posted in another thread
I know about the 50w 6.8 ohm resistors needed. My plan was to fit them into the adaptor cable. Ive re wired the cable for all the extra parts (2x resistors and bypass relay) just waiting for parts now.
The plan is to just use this cable for trailers when needed. It also means come MOT time they just test the oem tow elec loom.
Cheers
Spence
3rd Mar 2016 12:41 am
EstorilM
Member Since: 15 Oct 2009
Location: Virginia
Posts: 28
Maaaybe the export LR's got a different version of the "strobe" or something
Seriously though the pulse is so short it's hardly visible on all the trailers I've used (on both RRS and LR3) and clearly isn't any kind of indicator. It's about as distracting as the reflective trailer tape right next to the lights.
I believe I lost the trailer turn indicator on the dash when I put LED lights on my horse trailer though (which would also imply that the vehicle probably doesn't see anything when it's doing the "pulse test") I don't think anything changed though?
I don't know what the vehicle uses this pulse test for... the TCM for the ZF6HP has an independent load calculation which automatically enables the tow/haul shift program.
Neither my RRS or LR3 disabled the PDC when trailer was attached, though it's possible my PDC module was running an early software version. Kinda annoying.
As far as the air suspension going into a different mode, I'm not sure about this.. would it need to? Again mine behaves the same and autolevels / handles great regardless of electrics hooked up, LEDs, etc.. just same old height sensors / adjustment it always does when I add weight.|'99 Discovery II | 177k mi. | Kinversand | 7 pas, SLS, HK|
|'06 LR3 HSE Luxury | Chawton White | Cold Weather/Adaptive HL/RSE/Running Boards | '14 "blackout" LR4 tail lights, 2.5" lift rods, 20" black/machined stormers, 275/55/20 Falken Wildpeaks
3rd Mar 2016 1:36 am
lamb190
Member Since: 14 Nov 2015
Location: bristol
Posts: 46
Progress
Ive just slaved it up to the car/trailer and the bypass relay box clearly works. - no more blinking/strobing of LED trailer lights
Im waiting on some resistors. So hopefully i can make the car see the trailers connected.
I had some 10 ohm 3 watt reaistors that i tryed to slave it to see if it worked, but they got hot mega fast and may have blown.
3rd Mar 2016 1:13 pm
lamb190
Member Since: 14 Nov 2015
Location: bristol
Posts: 46
Ok so harness is built and tested. Worked a treat.
Resistors need to be wired in the before the bypasd relay or they wont have an effect.
Im sure many will look at the harness ive put together and say its OTT, in many ways it is...
But for me LED lights on a boat trailer are a must, and the resistors are needed, or when the car is tilted on the slipway, and a load (boat) is being winched up im sure the car will then be trying to self level and compensate.
4th Mar 2016 6:07 pm
Sly666
Member Since: 15 Dec 2014
Location: East Sussex
Posts: 459
Looks good, are you putting in a waterproof box?
Do you have a permanent +12v feed in the trailer socket to run the bypass relay?
I would be tempted to put some sort of heat sink on the back of those power resistors. Or better still mount it in a aluminium box to act as the heatsink.
LED lights on a boat trailer is great. No more friggin about wiggling bulbs trying to get a good connection.
4th Mar 2016 10:14 pm
lamb190
Member Since: 14 Nov 2015
Location: bristol
Posts: 46
With the 13 pin plug i think i have have constant 12v and ignition 12v.
I wired the bypass into the 12v ignition.
Also everything other than the resistors are shrink wrapped then sealed with epoxy resin.
The bypass has clear shrink wrap around it. I shrank the ends of that as much as poss then filled the gap with PU adhesive and then zip tied. So should be fine against rain and water spray.
Being clear rubber around the bypass i can easily see if water gets it.
Last edited by lamb190 on 4th Mar 2016 10:52 pm. Edited 1 time in total
4th Mar 2016 10:35 pm
Sloss
Member Since: 18 Aug 2013
Location: Aberdeenish
Posts: 1691
Quote:
The plan is to just use this cable for trailers when needed. It also means come MOT time they just test the oem tow elec loom.
I've never had my towing electrics tested as part of the MoT - or have I Stew,
2010 D4 gone but I really loved it
Went back to Merc - C350 AMG
4th Mar 2016 10:37 pm
lamb190
Member Since: 14 Nov 2015
Location: bristol
Posts: 46
Will they bother to remove the tow elec cover panel if its fitted... prob not.
There was a place i used to get MOTs done, and they used to find anything to fail my cars on. Like saying light bulbs work but give in correct beam patterns... crap like that... any how turned out that the MOT'd mite vans, fleet contracts... so had to fail cars as it would raise eyebrows with DVLA - So say anyhow.
4th Mar 2016 10:56 pm
lamb190
Member Since: 14 Nov 2015
Location: bristol
Posts: 46
Ok so i wasnt happy with what i made for an adaptor cable... so knocked this out instead..
Dont have a fog light on my trailers - so used that blue wire in the flex cable to run the ignition 12v from the 13pin plug.
9th Mar 2016 5:01 pm
Diggerdamo
Member Since: 30 Jan 2017
Location: Torbay
Posts: 1
I am so happy I have read this, exactly the same issue, thanks guys
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